Our 3M™ fire barrier plank PK39 is a pre-formed foam plank designed for easy installation to effectively seal larger openings against smoke, toxic gas and flame. It is simple to use and helps reduce sound transmission. When sealing larger cavities, use 3M™ fire barrier plank pk39 to restore the integrity of the wall with a simple "stack, sealant done" application, without the use of special tools. The blocks are engineered to remain securely in place, eliminating traditional wire mesh reinforcements. Pre-formed blocks help technicians fill large openings quickly. The material is easy to trim on-site without special tools, achieving a tight, custom fit. No cure time is required, which means installation is completed faster and the blocks are paintable with primer for a more seamless appearance.